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User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5) Gecko/20041215 Firefox/1.0 Red Hat/1.0-12.EL4
Description of problem:
Scenario: Regular user is connected to a VNC server via vncviewer. The machine running the VNC server is in run level 3 (no X11). Next, within vnc session, user does an SU to root in an xterm and runs an X11 app, or runs an su graphical application (such as up2date, system-config-users, etc). Spawn of the X11 window then fails, with an "Xlib" connection xxx refused by server" error.
Version-Release number of selected component (if applicable):
vnc-server-4.0-8.1
How reproducible:
Always
Steps to Reproduce:
1. Server machine must be booted in run level 3, running RHEL 4.
2. User logs into a VNC session running on that server.
3. User runs root app such as up2date or system-config-users, etc.
4. Or, instead of 3, user does an su in an xterm, and runs an X11 app.
Actual Results: X11 app doesn't start. Instead, "Xlib: connection xxx refused by server error" occurs.
Expected Results: X11 app should have created a new window and run.
Additional info:
Problem doesn't occur if machine is booted into run level 5.
Problem occurs only when booted into run level 3.
Problem never occured in previous versions of vnc-server, such as 4.0-0.beta4.1.4
Problem doesn't occur if 4.0-8.1 version of Xvnc is replaced with 4.0-0.beta4.1.4
Problem seems to be due to improper handling of xauth/magic cookies within Xvnc.

I can't reproduce this. Please provide more information:
1. Have you modified your .vnc/xstartup file?
2. What does '/usr/sbin/getenforce' say?
3. How are you starting VNC? Running 'vncserver' from the command line or
editing /etc/sysconfig/vncservers (or some other method?)